The warning comes as the latest figures show 314 cases of flu were reported in the Murrumbidgee Local Health District in the week ending June 30, a massive increase on the 159 cases reported in the previous seven days.

There have been 66 confirmed deaths of people aged over 60 years from flu-related complications since the beginning of the year, including nine deaths in the past week.

NSW Health director of communicable diseases, Dr Vicky Sheppeard, said there have been 26 influenza outbreaks in aged-care facilities just this week and unwell visitors are potentially putting loved ones at risk.

"It is important the community takes seriously the risks associated with the winter flu season," said MLHD's director of public health Tracey Oakman.

"The flu season is here and it is important that people, particularly vulnerable people, take care with regard to influenza. The flu virus is especially dangerous for elderly people, pregnant woman, Aboriginal people, very young children and people with underlying medical conditions," Mrs Oakman said.

She has reminded those people visiting friends and family in the hospital or aged care facilities to practice good hand hygiene by using the alcohol based gel or foam provided to reduce the spread of germs.

"Over the past few weeks, there has been an increase in influenza cases in the area notified to the local public health unit, and presenting to the local emergency department. We have also seen a number of cases in aged care facilities. In susceptible people, flu symptoms can quickly progress to become life-threatening," Mrs Oakman said.

In general, the flu is worse than a common cold, and symptoms such as fever, body aches, extreme tiredness, and dry cough are more common and intense, and often start suddenly, she said.

Colds are usually milder than the flu and symptoms generally develop over a longer period.

Mrs Oakman said while vaccination was the best protection against flu, there were some simple steps to help infection spreading, such as: